What to Expect in the First Trimester of Pregnancy – An Overview

The first trimester of your pregnancy is an exciting, yet nerve-racking, time. But, a little knowledge goes a long way towards helping you feel more confident and in control. Welcome to our overview of your first three months of pregnancy. Read on to learn more about the early symptoms, fetal developments, and important tasks of early pregnancy.

How Long is the First Trimester of Pregnancy?

The funny thing is that your first trimester begins BEFORE you actually conceive. Once you’ve had a positive pregnancy test result, your due date will be calculated from the first day of your last period. And, as your window of fertility is around 14 days into your menstrual cycle, in weeks one and two of pregnancy you’re not pregnant at all. But that’s just an interesting technicality. The first trimester of pregnancy lasts from the first day of your last period until the end of your 13th week of pregnancy.

If you need a little help working out what week you’re in and when your baby might arrive, try our handy Due Date Calculator tool for an accurate estimate.

First Trimester Symptoms:

Your body goes through numerous changes in the early stages of pregnancy, and it can be hard to keep up with the symptoms. It can also be difficult to tell normal, healthy symptoms from those that could be a sign of serious complications. We’ve divided the first trimester pregnancy symptoms into two groups – the harmless ones and the ones you should be calling your doctor about.

Common Early Pregnancy Symptoms:

Light Spotting:

As the embryo embeds in your uterus, you may notice some light spotting in your underwear. As long as this does not continue past week 4 of pregnancy and doesn’t become heavy bleeding, it’s nothing to worry about.

This is one of the most common, and most uncomfortable, symptoms of early pregnancy. Pregnancy nausea can start as early as week 5 of pregnancy and can last for up to four months (although most women find that it eases by the end of first trimester). It can also strike at any time in the day or night. It’s experienced by around 75% of pregnant women and, provided that you’re not losing a dramatic amount of weight, it’s nothing to worry about.

There are two reasons you might experience cramping in the first trimester: embryo embedding and the ligaments around your uterus stretching as you grow. As long as the pain is not intense or persistent, it’s nothing to worry about.

Fatigue:

Your body is working hard to create a safe home for your baby and to begin the first stages of fetal development. The pregnancy hormones doing the job can make you feel tired and sluggish.

Mood Swings:

Another sign that those hormones are working hard. Try and stay relaxed and get plenty of fresh air and exercise. Take a few deep breaths if you can feel a mood swing coming on – you don’t want to lash out at the people closest to you.

Tingling or Sore Nipples and Breasts:

Tender breasts is likely to be one of your first signs of pregnancy (anytime from 2 weeks on). It’s caused by hormonal changes – your body is already preparing for nursing. Buy a really comfortable bra – avoid lace or other irritating materials.

Needing to Pee (all the Time!):

Your growing uterus may put pressure on your bladder and you may need to urinate more frequently than usual.

Weight Gain:

Your first trimester weight gain should be around 3 to 6 pounds. Your baby doesn’t weigh anything like that much yet but increased blood volume, amniotic fluid, and your growing uterus add weight. Try not to fall into the “eating for two” trap. Eat a nutritious pregnancy diet to give your baby the best start in life.

Constipation:

The pregnancy hormones can make your metabolism sluggish.Include lots of high-fiber foods in your pregnancy diet and drink plenty of water.

Vaginal Discharge:

It’s not uncommon to see an increase in vaginal discharge during the first trimester of pregnancy. It should be thin and milky white and have only a slight odor. You can use a panty liner but not a tampon. If the color, smell, or volume of the discharge is unusual, you should get in touch with your doctor.

Risks in Early Pregnancy:

Miscarriage (Spontaneous Abortion):

Unfortunately, up to 20% of pregnancies miscarry in the first 13 weeks. Most miscarriages are not preventable and are the result of chromosomal abnormalities or unsuccessful embryo embedding. It’s heartbreaking when this happens. But the fact that you were pregnant is a sign that you can conceive naturally and should continue trying for a baby. Lifestyle choices such as smoking, drinking alcohol, and recreational drug use can increase your chances of miscarriage. By the end of the first trimester, the chances of miscarriage decrease significantly, which is why many couples wait till then to announce their pregnancy.

Ectopic Pregnancy (Tubal Pregnancy):

Another type of unviable pregnancy is an ectopic pregnancy, where the embryo embeds in the fallopian tubes instead of the uterus. An ectopic pregnancy puts the mother at serious risk and usually needs to be surgically removed. Only about 1% of pregnancies are ectopic.

High-Risk Pregnancy Symptoms in the First Trimester:

If you have any of the following symptoms you should get medical help immediately:

Bleeding

Intense or Persistent Abdominal Pain

Severe Back Pain

Pelvic Pain

Passing Tissue or Clots

Sudden Stoppage of Pregnancy Symptoms (e.g. morning sickness)

No weight gain or rapid weight gain

Dizziness or fainting

Green or foul-smelling vaginal discharge

First Trimester Care:

On that note, have you thought about who your pregnancy professionals will be? It’s important to have a team of professionals and advisors you trust to work with you throughout your pregnancy, and the first trimester is the perfect time to get started.

Your prenatal care should be ongoing. If you’re regularly checking in about symptoms and developments, you’re much less likely to find yourself in a crisis situation. As the old saying goes, prevention is better than cure. Click through here to read about your options for professional prenatal care.

In addition to your one on one pregnancy care, it is highly recommended that you take a course of antenatal classes. Not only will you get all the information you need about pregnancy, labor, and childbirth, you’ll also meet people at the same stage of pregnancy as you – talking about it makes it so much easier! There are all sorts of styles of childbirth education, including Lamaze Classes, The Bradley Method, and Hypnobirthing. Read more about each of them here.

First Trimester Screening:

Particularly if you are 40 or over, you may want to consider having this non-invasive procedure to test your fetus for chromosomal abnormalities, such as Down Syndrome. First-trimester screening uses a combination of ultrasound analysis and maternal blood screening to identify risk factors and probabilities. Read more about it here and check with your obstetrician about whether this procedure is right for you.

First Trimester Ultrasound:

Most women have their first ultrasound at between 6 and 8 weeks pregnant. At this appointment, the ob-gyn will check that your baby’s heartbeat is healthy, examine your reproductive system, rule out the possibility of ectopic pregnancy, and adjust your due date based on Baby’s growth and development.

First Trimester Baby Development:

It’s not only your body making dramatic changes. Your baby is also developing rapidly! In fact, the first trimester is the most critical period of fetal development. By the end of the third month, your baby will be fully formed, with everything from a nervous system to fingernails. After that, the second and third trimesters focus on growth. Here are some of the exciting fetal developments in the first three months of pregnancy:

First Month of Pregnancy:

The Embryo Embeds in Your Uterus: If all has gone well with conception, the fertilized embryo will burrow into your uterus and begin to develop.

The Amniotic Sac Forms: A water-tight sac of fluid will form around your embryo and protect it throughout your pregnancy.

Your Placenta Forms: This miraculous organ has a round, flat shape and will transfer nutrients from your body to your baby’s for the duration of the pregnancy

Baby’s Face begins to Take Shape: A primitive little face forms in the first month of pregnancy, with dark circles where the eyes will be and the beginnings of a mouth.

He or She is the Size of a Grain of Rice! By the end of the first month, your baby should be around a quarter of an inch long – just a tiny grain of rice!

Second Month of Pregnancy:

More Facial Development: The eyes continue to form and tiny flaps of skin which will later become ears grow on the side of the face.

Brain and Nervous System: The neural tube, which includes the brain, spinal cord, and nervous system, forms.

Movements Begin: Even though you won’t feel any “kicks” for several months, your baby is already moving inside the womb.

Bones are Forming: Soft cartilage forms and is slowly replaced by harder bone.

Third Month of Pregnancy:

He or She is Now a Fetus! That little embryo is now classed as a fetus and will be around an inch long and weigh a third of an ounce. Currently, the head makes up about a third of the baby!

Arms and Legs, Hands and Feet, Fingers and Toes: Baby’s limbs form – right down to finger and toenails!

Organs and Systems: Sensory, reproductive and vital organs are in place and begin to work.

Your Baby is Now Fully Formed! By the end of the first trimester, your baby will be fully formed (although he or she will have lots of growing left to do over the next six months!). The baby should weigh around one ounce and be 3 to 4 inches long.

Learn More about the First Trimester Weeks:

Need more detailed information about the changes and developments in each of the first trimester pregnancy weeks? Just click on your week and we’ll tell you all about your baby’s growth, important advice, and first trimester symptoms week by week:

More Pregnancy Articles and Links:

Your body will be Baby’s home for the next nine months. That means, to look after your baby, you have to take good care of your body! Check out our comprehensive guide to eating well and staying active for a healthy pregnancy and a healthy baby.

Yoga during pregnancy has numerous health benefits you might not have thought of. It helps you strengthen and prepare your body for labor, encourages relaxation, helps you relieve the pain of pregnancy aches and cramps, and much more. Read more here!

Morning sickness is one of the most common symptoms of the first trimester of pregnancy and around three-quarters of women experience it. Unfortunately, there’s no way to magically make it go away. But, with a few tweaks to your nutrition and lifestyle, you can make pregnancy nausea a little more bearable. Find out how here.